1. Field of the Invention
The present invention relates to a process for preparing optical active tryptophanes by biochemical asymmetric hydrolysis of DL-tryptophane amides, in which an amidase derived from a microorganism is utilized.
2. Description of the Prior Art
It is well-known in the art that L-tryptophanes and D-tryptophanes are optically active and have different properties and uses. For instance, L-tryptophane is an important compound as an essential amino acid and is suitable for use in an amino acid infusion solution, animal food stuff additives, hypnotizing agent and the like. On the other hand, D-tryptophane is useful as, for example, dentifrice additives.
Many organic synthesis methods for preparing tryptophanes have been heretofore proposed. However, when the tryptophanes are prepared by organic synthesis methods, the products are obtained in the form of mixtures of D-tryptophanes and L-tryptophanes, i.e. racemic mixtures. Therefore, the effective optical resolution of DL-tryptophanes is an extremely important problem to be solved in the art.
Proposed optical resolution methods of DL-tryptophanes are only those in which hydantoin or N-acyl derivatives of DL-tryptophanes are used as a substrate and in which microorganisms capable of producing hydantoinase or acylase are interacted with the substrate. Thus, the development of the substrate and the microorganisms used in the field of the biochemical optical resolution of DL-tryptophanes are extremely limited.